* {
    padding: 0;
    margin: 0;
    font-size: 18px;
    line-height: 50px;
}
ul {
    list-style: none;
}
.selectParent {
    width: 800px;
    margin: 100px auto;
}
.select {
    float: left;
    display: block;
    width: 100px;
    height: 200px;
}
a {
    display: block;
    width: 100px;
    height: 50px;
    background-color: orange;
    text-decoration: none;
    color: black;
    box-sizing: border-box;
    border-right: 2px solid gray;
}
.select ul {
    display: none;
    width: 100px;
    height: 150px;
    background-color: skyblue;
}
.select ul li {
    display: block;
    width: 100px;
    height: 50px;
    box-sizing: border-box;
    border-bottom: 2px solid gray;
}